On Mon, 2010-01-11 at 15:53 -0500, M. Ranganathan wrote: > I have found the References header a very handy way of tracking causal > chains in a B2BUA. I have added a parameter x-sipx-branchid which > contains the topmost via header of the transaction that triggers the > request containing the References header. This + call ID allows us to > nicely tie transactions together. > > However I do not understand the purpose of the rel parameter. I would > like to see it be used to record the method of the triggering request. > > For example rel=INVITE > > As such rel=CHAIN does not provide much information.
The rel parameter records the manner in which the current dialog relates to the named dialog. See http://tools.ietf.org/html/draft-worley-references-05#section-2: The currently defined values of the "rel" parameter are: "chain" meaning that this request is the logical continuation of the dialog with the specified Call-Id through a B2BUA or the like, in that it will carry media that have the same meaning to the user "inquiry" meaning that this request was generated to obtain information needed to properly process a request with the specified Call-Id. (For example, in section 2.16, "Call Pickup" of [service-examples], a SUBSCRIBE is generated to discover the UA which sent an INVITE to a designated AOR.) "join" - this value is permanently reserved so that it may be used as a value of cognate data items when describing dialogs related by a "Join" header "refer" meaning that this request was generated due to a REFER with the specified Call-Id "replaces" - this value is permanently reserved so that it may be used as a value of cognate data items when describing dialogs related by a "Replaces" header "service" means that this dialog is to obtain "service media" for use by the dialog with the specified Call-Id. "Service media" includes music-on-hold, alert tones, and the like. "sequel" means that this dialog is the continuation of the conversation carried by the dialog with the specified Call-Id "xfer" meaning that the dialog of this message and the dialog with the specified Call-Id are the two legs of a consultative (or attended) transfer. One endpoint of each dialog will become an endpoint of the final dialog. > I would > like to see it be used to record the method of the triggering request. > > For example rel=INVITE Why not use "x-sipx-method=INVITE"? Dale _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev sipXecs IP PBX -- http://www.sipfoundry.org/
